Fixed iOS NumericOverFlow Exceptions for color.cs and constantbuffer.PlatformInitialize
Fixed xml namespaces.
Added xml to assets project.
Changed  to unchecked instead of bitmask and MathHelper.
Fixed incorrect public access.
Added missing ContentSerializerCollectionItemNameAttribute.
Merge pull request #2654 from SickheadGames/access

Access & ContentSerializerCollectionItemNameAttribute
Merge branch 'develop' into intermediate
Fixed some missing types.
Added intermediate deserializer unit tests.
Merge pull request #2655 from SickheadGames/intermediate

Intermediate Deserializer Unit Tests
Merge pull request #2650 from josant/iosmathfixes

Fixed iOS NumericOverFlow Exceptions
Fixed bug in detection of "natural" orientation of Android device.

Value of "natural" orientation is computed on first OnOrientationChanged() call (not in ctor, because it may return invalid value if called too early).
Orientation listener is active between Activity.OnResume()/OnPause() calls.
Orientation value of OrientationUnknown (-1) is ignored.